"Do you remember the thick stuff that Dr. Thornton showed us in
IV. Chemistry the other day?"
"Great Scott!" breathed Dave Darrin, anxiously. "You don't mean nitroglycerine?"
"But I do!" Dick nodded, energetically.
"Wow! Don't stir from here. I'll call the night manager."
Night Manager Drowan came over at once, eyeing the box and the tiny pool of thick stuff.
"I never saw nitroglycerine but once," remarked Mr. Drowan, nervously. "I should say this stuff looks just like it. We won't take any chances, anyway. Dave, you go to the telephone, and notify the police. Your friends can stand guard over the box so that no one gets a chance to go near it."
But, while Dave was at the 'phone, Mr. Drowan hung over the box as though fascinated.
"It takes fire to set this stuff off, doesn't it?" he asked.
"No," Dick replied. "If it's nitroglycerine in that box, a light, sharp blow might be enough to do the trick. At least, that was about what Dr. Thornton said."
Dave came back with word that the police would send some one at once.